我想在ViewPager中添加3个底部点，像这样。
我使用FragmentActivity和支持库ViewPager。
当前回答
下面是我如何做到这一点，有点类似于上面的解决方案。只要确保在下载完所有图像后调用loadDots()方法即可。
private int dotsCount;
private TextView dotsTextView[];
private void setupAdapter() {
adapter = new SomeAdapter(getContext(), images);
viewPager.setAdapter(adapter);
viewPager.setCurrentItem(0);
viewPager.addOnPageChangeListener(viewPagerPageChangeListener);
}
private final ViewPager.OnPageChangeListener viewPagerPageChangeListener = new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
@Override
public void onPageSelected(int position) {
for (int i = 0; i < dotsCount; i++)
dotsTextView[i].setTextColor(Color.GRAY);
dotsTextView[position].setTextColor(Color.WHITE);
}
@Override
public void onPageScrollStateChanged(int state) {}
};
protected void loadDots() {
dotsCount = adapter.getCount();
dotsTextView = new TextView[dotsCount];
for (int i = 0; i < dotsCount; i++) {
dotsTextView[i] = new TextView(getContext());
dotsTextView[i].setText(R.string.dot);
dotsTextView[i].setTextSize(45);
dotsTextView[i].setTypeface(null, Typeface.BOLD);
dotsTextView[i].setTextColor(android.graphics.Color.GRAY);
mDotsLayout.addView(dotsTextView[i]);
}
dotsTextView[0].setTextColor(Color.WHITE);
}
XML
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="180dp"
android:background="#00000000"/>
<ImageView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/introImageView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<LinearLayout
android:id="@+id/image_count"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#00000000"
android:gravity="center|bottom"
android:orientation="horizontal"/>
</FrameLayout>
其他回答
我的手工解决方案:
在布局中:
<LinearLayout
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/dots"
/>
在活动中
private final static int NUM_PAGES = 5;
private ViewPager mViewPager;
private List<ImageView> dots;
@Override
protected void onCreate(Bundle savedInstanceState) {
// ...
addDots();
}
public void addDots() {
dots = new ArrayList<>();
LinearLayout dotsLayout = (LinearLayout)findViewById(R.id.dots);
for(int i = 0; i < NUM_PAGES; i++) {
ImageView dot = new ImageView(this);
dot.setImageDrawable(getResources().getDrawable(R.drawable.pager_dot_not_selected));
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT
);
dotsLayout.addView(dot, params);
dots.add(dot);
}
mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
selectDot(position);
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
public void selectDot(int idx) {
Resources res = getResources();
for(int i = 0; i < NUM_PAGES; i++) {
int drawableId = (i==idx)?(R.drawable.pager_dot_selected):(R.drawable.pager_dot_not_selected);
Drawable drawable = res.getDrawable(drawableId);
dots.get(i).setImageDrawable(drawable);
}
}
我想针对上述问题发布一个更简单的解决方案，指标数字可以动态更改，只需更改一个变量值dotCounts=x，我所做的是这样的。
在可绘制文件夹中为页面选定指标创建一个名为“item_selected”的xml文件。
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval" android:useLevel="true"
android:dither="true">
<size android:height="8dp" android:width="8dp"/>
<solid android:color="@color/image_item_selected_for_dots"/>
</shape>
为未选中的指示器再创建一个名为“item_unselected”的xml文件
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="oval" android:useLevel="true"
android:dither="true">
<size android:height="8dp" android:width="8dp"/>
<solid android:color="@color/image_item_unselected_for_dots"/>
</shape>
现在将这部分代码添加到您想要显示指示器的位置，例如在Layout XML文件中的viewPager下面。
<RelativeLayout
android:id="@+id/viewPagerIndicator"
android:layout_width="match_parent"
android:layout_below="@+id/banner_pager"
android:layout_height="wrap_content"
android:gravity="center">
<LinearLayout
android:id="@+id/viewPagerCountDots"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerHorizontal="true"
android:gravity="center"
android:orientation="horizontal" />
</RelativeLayout>
将此函数添加到布局膨胀的活动文件或与上述xml文件相关的活动文件之上
private int dotsCount = 5; //No of tabs or images
private ImageView[] dots;
LinearLayout linearLayout;
private void drawPageSelectionIndicators(int mPosition){
if(linearLayout!=null) {
linearLayout.removeAllViews();
}
linearLayout=(LinearLayout)findViewById(R.id.viewPagerCountDots);
dots = new ImageView[dotsCount];
for (int i = 0; i < dotsCount; i++) {
dots[i] = new ImageView(context);
if(i==mPosition)
dots[i].setImageDrawable(getResources().getDrawable(R.drawable.item_selected));
else
dots[i].setImageDrawable(getResources().getDrawable(R.drawable.item_unselected));
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT
);
params.setMargins(4, 0, 4, 0);
linearLayout.addView(dots[i], params);
}
}
最后，在你的onCreate方法中添加以下代码来引用你的布局和处理页面选择的位置
drawPageSelectionIndicators(0);
mPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
drawPageSelectionIndicators(position);
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
viewPager.addOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
switch (position) {
case 0:
img_page1.setImageResource(R.drawable.dot_selected);
img_page2.setImageResource(R.drawable.dot);
img_page3.setImageResource(R.drawable.dot);
img_page4.setImageResource(R.drawable.dot);
break;
case 1:
img_page1.setImageResource(R.drawable.dot);
img_page2.setImageResource(R.drawable.dot_selected);
img_page3.setImageResource(R.drawable.dot);
img_page4.setImageResource(R.drawable.dot);
break;
case 2:
img_page1.setImageResource(R.drawable.dot);
img_page2.setImageResource(R.drawable.dot);
img_page3.setImageResource(R.drawable.dot_selected);
img_page4.setImageResource(R.drawable.dot);
break;
case 3:
img_page1.setImageResource(R.drawable.dot);
img_page2.setImageResource(R.drawable.dot);
img_page3.setImageResource(R.drawable.dot);
img_page4.setImageResource(R.drawable.dot_selected);
break;
default:
break;
}
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
});
如果有人想要构建一个带有缩略图作为指示器的viewPager，可以选择使用这个库: 用于viewPager的ThumbIndicator，也可以将图像链接作为资源。
下面是我如何做到这一点，有点类似于上面的解决方案。只要确保在下载完所有图像后调用loadDots()方法即可。
private int dotsCount;
private TextView dotsTextView[];
private void setupAdapter() {
adapter = new SomeAdapter(getContext(), images);
viewPager.setAdapter(adapter);
viewPager.setCurrentItem(0);
viewPager.addOnPageChangeListener(viewPagerPageChangeListener);
}
private final ViewPager.OnPageChangeListener viewPagerPageChangeListener = new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
@Override
public void onPageSelected(int position) {
for (int i = 0; i < dotsCount; i++)
dotsTextView[i].setTextColor(Color.GRAY);
dotsTextView[position].setTextColor(Color.WHITE);
}
@Override
public void onPageScrollStateChanged(int state) {}
};
protected void loadDots() {
dotsCount = adapter.getCount();
dotsTextView = new TextView[dotsCount];
for (int i = 0; i < dotsCount; i++) {
dotsTextView[i] = new TextView(getContext());
dotsTextView[i].setText(R.string.dot);
dotsTextView[i].setTextSize(45);
dotsTextView[i].setTypeface(null, Typeface.BOLD);
dotsTextView[i].setTextColor(android.graphics.Color.GRAY);
mDotsLayout.addView(dotsTextView[i]);
}
dotsTextView[0].setTextColor(Color.WHITE);
}
XML
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="180dp"
android:background="#00000000"/>
<ImageView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/introImageView"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<LinearLayout
android:id="@+id/image_count"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#00000000"
android:gravity="center|bottom"
android:orientation="horizontal"/>
</FrameLayout>
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